Impedance meters are known for measuring the impedance of a person's body and from the impedance, the device determines a value representing the person's body fat. More particularly, one known device includes a table top analog impedance meter that displays a resistance value. A user can then enter the displayed resistance value into a personal computer that stores a body fat software algorithm. Another known device includes an integrated impedance meter and lap top computer that can be connected to a printer. A battery powered hand-held device is also known that includes a microprocessor control and provides body impedance measurements but does not provide the resistance and reactance components of the measured impedance. Each of the above known devices has one or more problems with: lack of accuracy; being hard to use due to size; being inflexible and non-updatable; and providing limited information to a user.